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7.8

CVE-2026-68330: Linux kernel NPU mailbox may return stale data

CVE-2026-68330 · published 2 months ago
Summary

The Linux kernel’s handling of messages sent to the NPU (a special processor) can leave old information in the CPU’s cache, so the system may read outdated results instead of the NPU’s reply. This occurs on certain hardware without automatic cache coordination and can cause silent data errors. Updating the kernel to use a two‑way data transfer mode fixes the issue; ensure your Linux distribution is patched to the latest version.

What to do
  • Update debian linux to version 7.1.6-1.
  • Update linux kernel to version 7.1.6.
  • Update linux linux to version 76fc5604308a109bf5838c2a0a0eb3ac6819f1ea or later.
Affected software
Ecosystem VendorProductAffected versions
Debian:14 debian linux < 7.1.6-1
Fix: upgrade to 7.1.6-1
Ubuntu:18.04:LTS canonical linux-gke-4.15 All versions
Ubuntu:18.04:LTS canonical linux-gke-5.4 All versions
Ubuntu:18.04:LTS canonical linux-gkeop-5.4 All versions
Ubuntu:18.04:LTS canonical linux-hwe All versions
Ubuntu:18.04:LTS canonical linux-hwe-edge All versions
Ubuntu:18.04:LTS canonical linux-oem All versions
Ubuntu:18.04:LTS canonical linux-oracle-5.0 All versions
Ubuntu:18.04:LTS canonical linux-oracle-5.3 All versions
Ubuntu:20.04:LTS canonical linux-aws-5.11 All versions
Ubuntu:20.04:LTS canonical linux-aws-5.13 All versions
Ubuntu:20.04:LTS canonical linux-aws-5.8 All versions
Ubuntu:20.04:LTS canonical linux-azure-5.11 All versions
Ubuntu:20.04:LTS canonical linux-azure-5.13 All versions
Ubuntu:20.04:LTS canonical linux-azure-5.8 All versions
Ubuntu:20.04:LTS canonical linux-azure-fde All versions
Ubuntu:20.04:LTS canonical linux-gcp-5.11 All versions
Ubuntu:20.04:LTS canonical linux-gcp-5.13 All versions
Ubuntu:20.04:LTS canonical linux-gcp-5.8 All versions
Ubuntu:20.04:LTS canonical linux-gke All versions
Ubuntu:20.04:LTS canonical linux-gke-5.15 All versions
Ubuntu:20.04:LTS canonical linux-gkeop All versions
Ubuntu:20.04:LTS canonical linux-gkeop-5.15 All versions
Ubuntu:20.04:LTS canonical linux-hwe-5.11 All versions
Ubuntu:20.04:LTS canonical linux-hwe-5.13 All versions
Ubuntu:20.04:LTS canonical linux-hwe-5.8 All versions
Ubuntu:20.04:LTS canonical linux-intel-5.13 All versions
Ubuntu:20.04:LTS canonical linux-oem-5.10 All versions
Ubuntu:20.04:LTS canonical linux-oem-5.13 All versions
Ubuntu:20.04:LTS canonical linux-oem-5.14 All versions
Ubuntu:20.04:LTS canonical linux-oem-5.6 All versions
Ubuntu:20.04:LTS canonical linux-oracle-5.11 All versions
Ubuntu:20.04:LTS canonical linux-oracle-5.13 All versions
Ubuntu:20.04:LTS canonical linux-oracle-5.8 All versions
Ubuntu:20.04:LTS canonical linux-raspi2 All versions
Ubuntu:20.04:LTS canonical linux-riscv All versions
Ubuntu:20.04:LTS canonical linux-riscv-5.11 All versions
Ubuntu:20.04:LTS canonical linux-riscv-5.8 All versions
Ubuntu:22.04:LTS canonical linux-allwinner-5.19 All versions
Ubuntu:22.04:LTS canonical linux-aws-5.19 All versions
Ubuntu:22.04:LTS canonical linux-aws-6.2 All versions
Ubuntu:22.04:LTS canonical linux-aws-6.5 All versions
Ubuntu:22.04:LTS canonical linux-azure-5.19 All versions
Ubuntu:22.04:LTS canonical linux-azure-6.2 All versions
Ubuntu:22.04:LTS canonical linux-azure-6.5 All versions
Ubuntu:22.04:LTS canonical linux-azure-fde-5.19 All versions
Ubuntu:22.04:LTS canonical linux-azure-fde-6.2 All versions
Ubuntu:22.04:LTS canonical linux-gcp-5.19 All versions
Ubuntu:22.04:LTS canonical linux-gcp-6.2 All versions
Ubuntu:22.04:LTS canonical linux-gcp-6.5 All versions
Showing 50 of 134. Show the rest
Ecosystem VendorProductAffected versions
Ubuntu:22.04:LTS canonical linux-hwe-5.19 All versions
Ubuntu:22.04:LTS canonical linux-hwe-6.2 All versions
Ubuntu:22.04:LTS canonical linux-hwe-6.5 All versions
Ubuntu:22.04:LTS canonical linux-intel-iot-realtime All versions
Ubuntu:22.04:LTS canonical linux-lowlatency-hwe-5.19 All versions
Ubuntu:22.04:LTS canonical linux-lowlatency-hwe-6.2 All versions
Ubuntu:22.04:LTS canonical linux-lowlatency-hwe-6.5 All versions
Ubuntu:22.04:LTS canonical linux-nvidia-6.2 All versions
Ubuntu:22.04:LTS canonical linux-nvidia-6.5 All versions
Ubuntu:22.04:LTS canonical linux-oem-5.17 All versions
Ubuntu:22.04:LTS canonical linux-oem-6.0 All versions
Ubuntu:22.04:LTS canonical linux-oem-6.1 All versions
Ubuntu:22.04:LTS canonical linux-oem-6.5 All versions
Ubuntu:22.04:LTS canonical linux-oracle-6.5 All versions
Ubuntu:22.04:LTS canonical linux-realtime All versions
Ubuntu:22.04:LTS canonical linux-riscv All versions
Ubuntu:22.04:LTS canonical linux-riscv-5.19 All versions
Ubuntu:22.04:LTS canonical linux-riscv-6.5 All versions
Ubuntu:22.04:LTS canonical linux-starfive-5.19 All versions
Ubuntu:22.04:LTS canonical linux-starfive-6.2 All versions
Ubuntu:22.04:LTS canonical linux-starfive-6.5 All versions
Ubuntu:24.04:LTS canonical linux-aws-6.14 All versions
Ubuntu:24.04:LTS canonical linux-aws-6.17 All versions
Ubuntu:24.04:LTS canonical linux-aws-7.0 All versions
Ubuntu:24.04:LTS canonical linux-azure-6.11 All versions
Ubuntu:24.04:LTS canonical linux-azure-6.14 All versions
Ubuntu:24.04:LTS canonical linux-azure-6.17 All versions
Ubuntu:24.04:LTS canonical linux-azure-fde-6.14 All versions
Ubuntu:24.04:LTS canonical linux-azure-fde-6.17 All versions
Ubuntu:24.04:LTS canonical linux-azure-nvidia-6.14 All versions
Ubuntu:24.04:LTS canonical linux-gcp-6.11 All versions
Ubuntu:24.04:LTS canonical linux-gcp-6.14 All versions
Ubuntu:24.04:LTS canonical linux-gcp-6.17 All versions
Ubuntu:24.04:LTS canonical linux-hwe-6.11 All versions
Ubuntu:24.04:LTS canonical linux-hwe-6.14 All versions
Ubuntu:24.04:LTS canonical linux-hwe-6.17 All versions
Ubuntu:24.04:LTS canonical linux-hwe-7.0 All versions
Ubuntu:24.04:LTS canonical linux-lowlatency-hwe-6.11 All versions
Ubuntu:24.04:LTS canonical linux-nvidia-6.11 All versions
Ubuntu:24.04:LTS canonical linux-nvidia-6.17 All versions
Ubuntu:24.04:LTS canonical linux-nvidia-7.0 All versions
Ubuntu:24.04:LTS canonical linux-oem-6.11 All versions
Ubuntu:24.04:LTS canonical linux-oem-6.14 All versions
Ubuntu:24.04:LTS canonical linux-oem-6.17 All versions
Ubuntu:24.04:LTS canonical linux-oem-6.8 All versions
Ubuntu:24.04:LTS canonical linux-oracle-6.14 All versions
Ubuntu:24.04:LTS canonical linux-oracle-6.17 All versions
Ubuntu:24.04:LTS canonical linux-raspi-realtime All versions
Ubuntu:24.04:LTS canonical linux-realtime All versions
Ubuntu:24.04:LTS canonical linux-riscv All versions
Ubuntu:24.04:LTS canonical linux-riscv-6.14 All versions
Ubuntu:24.04:LTS canonical linux-riscv-6.17 All versions
Ubuntu:24.04:LTS canonical linux-riscv-7.0 All versions
Ubuntu:Nvidia-BlueField:24.04:LTS canonical linux-bluefield All versions
Ubuntu:Pro:Realtime:24.04:LTS canonical linux-realtime-6.14 All versions
Ubuntu:Pro:Realtime:24.04:LTS canonical linux-realtime-6.17 All versions
Ubuntu:26.04:LTS canonical linux All versions
Ubuntu:26.04:LTS canonical linux-aws All versions
Ubuntu:26.04:LTS canonical linux-azure All versions
Ubuntu:26.04:LTS canonical linux-azure-fde All versions
Ubuntu:26.04:LTS canonical linux-gcp All versions
Ubuntu:26.04:LTS canonical linux-gke All versions
Ubuntu:26.04:LTS canonical linux-ibm All versions
Ubuntu:26.04:LTS canonical linux-nvidia All versions
Ubuntu:26.04:LTS canonical linux-nvidia-bos All versions
Ubuntu:26.04:LTS canonical linux-oem-7.0 All versions
Ubuntu:26.04:LTS canonical linux-oracle All versions
Ubuntu:26.04:LTS canonical linux-raspi All versions
Ubuntu:26.04:LTS canonical linux-realtime All versions
Ubuntu:26.04:LTS canonical linux-riscv All versions
Linux linux kernel >= 6.19.0, < 7.1.6
Fix: upgrade to 7.1.6
Ubuntu:24.04:LTS canonical linux-azure-7.0 All versions
Ubuntu:24.04:LTS canonical linux-azure-fde-7.0 All versions
Ubuntu:24.04:LTS canonical linux-gcp-7.0 All versions
Ubuntu:24.04:LTS canonical linux-oracle-7.0 All versions
– linux linux < 76fc5604308a109bf5838c2a0a0eb3ac6819f1ea
6.16
Ubuntu:16.04:LTS canonical linux-hwe-edge All versions
Ubuntu:18.04:LTS canonical linux-aws-5.0 All versions
Ubuntu:18.04:LTS canonical linux-aws-5.3 All versions
Ubuntu:18.04:LTS canonical linux-azure All versions
Ubuntu:18.04:LTS canonical linux-azure-5.3 All versions
Ubuntu:18.04:LTS canonical linux-azure-edge All versions
Ubuntu:18.04:LTS canonical linux-gcp All versions
Ubuntu:18.04:LTS canonical linux-gcp-5.3 All versions
Original advisory text
In the Linux kernel, the following vulnerability has been resolved: net: airoha: Fix DMA direction for NPU mailbox buffer airoha_npu_send_msg() always maps the mailbox buffer with DMA_TO_DEVICE, bu...
In the Linux kernel, the following vulnerability has been resolved: net: airoha: Fix DMA direction for NPU mailbox buffer airoha_npu_send_msg() always maps the mailbox buffer with DMA_TO_DEVICE, but some callers expect the NPU to write response data back into the same buffer: - airoha_npu_wlan_msg_get() (NPU_OP_GET): NPU writes response into the buffer, then the caller reads it via memcpy() - airoha_npu_ppe_stats_setup() (NPU_OP_SET): NPU writes back npu_stats_addr field in the response On non-cache-coherent architectures like EN7581 (Cortex-A53 without hardware cache coherency for NPU DMA), DMA_TO_DEVICE unmap is a no-op — it does not invalidate the CPU cache. If the NPU-written cache line is still present in the CPU cache when the caller reads the buffer, the CPU observes stale data instead of the NPU response. This is a timing-sensitive bug: small mailbox buffers (~24 bytes) typically fit in a single cache line and may survive in the cache until the caller reads them, producing silent data corruption rather than a crash. The bug is more likely to trigger when the caller reads the response immediately after dma_unmap_single() without intervening cache-evicting operations. Fix by using DMA_BIDIRECTIONAL for both map and unmap, which ensures dma_unmap_single() invalidates the CPU cache on non-coherent systems. The mailbox buffers are small so there is no performance concern.
Fix within
Internet-facing 14 days
Internal At next upgrade
  • Not known to be exploited
  • Needs hands-on effort to exploit (estimated)
  • Gives an attacker full control (estimated)
Severity
7.8 High
Exploitation
<1% chance of attack within 30 days
Timeline
Published10 Aug 2026
Updated26 Oct 2026
First seen10 Aug 2026
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